I have begun using a free utility called AudioUnit Manager from Audiofile Engineering. http://www.audiofile-engineering.com/audiounitmanager/
In its fullest development, it will allow you to create custom sets of AudioUnits to load with specific programs. Thus for Finale 2008 for Mac, which currently has a bug in the loading of AU's, I can create a custom set that loads only the specific AU's that I need for Finale (Kontakt 2, Kontakt 3, Kontakt Player 2, and Smart Music Softsynth). Finale loads much more quickly.
I say in its fullest development because there is currently a bug that will only allow you to have one custom set. The developer is aware and is currently working to remedy this in an upcoming update. For me at this point having only one custom set is fine because I only have the one program with issues regarding multiple AU's.
I hope that some of you Mac users out there who may be experiencing issues with Finale 2008 and the loading of AU's may find this utility useful.